muhammad abrar [email protected] +. m uhammad a brar ???? ms (computer science) gold medal...
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MUHAMMAD ABRAR????MUHAMMAD ABRAR???? MS (Computer Science) Gold MedalMS (Computer Science) Gold Medal
◦ Specialization in Database SystemsSpecialization in Database Systems Research PublicationResearch Publication
M. Abrar, Z. Jan, Dr A.M. Mirza S. Bashir “Seasonal to M. Abrar, Z. Jan, Dr A.M. Mirza S. Bashir “Seasonal to Interannual Climate Prediction Using Data Mining Interannual Climate Prediction Using Data Mining technique KNN” Springer Verlag Communications in technique KNN” Springer Verlag Communications in Computer and Information Science Series Book. 2008 Computer and Information Science Series Book. 2008
Research Areas: Data Mining , Data Ware Research Areas: Data Mining , Data Ware Housing, Distributed DatabaseHousing, Distributed Database
Areas of expertise : Programming (.NET (Visual Areas of expertise : Programming (.NET (Visual Basic, Visual C++ etc), C++, JAVA)Basic, Visual C++ etc), C++, JAVA)OOP Analysis, Structure Analysis and DesigningOOP Analysis, Structure Analysis and Designing
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MUHAMMAD ABRAR???? MUHAMMAD ABRAR???? (CONT’D)(CONT’D)
ExperienceExperience◦ January 2009 – ---- January 2009 – ---- (kardan Institute of Higher Education, Kabul)(kardan Institute of Higher Education, Kabul)
◦ Assistant Professor In Computer ScienceAssistant Professor In Computer Science◦ September 2006 – Dec 2008 September 2006 – Dec 2008 (IBMS/CS , Agricultural University (IBMS/CS , Agricultural University
Peshawar)Peshawar) Lecturer In Computer Science,Lecturer In Computer Science, Assistant In-charge Computer ScienceAssistant In-charge Computer Science
◦ September 2002- August 2006 September 2002- August 2006 (Govt. College of Commerce (Govt. College of Commerce Mardan)Mardan) Computer InstructorComputer Instructor In-charge Computer Literacy Program.In-charge Computer Literacy Program.
◦ February 2004 – August 2006 February 2004 – August 2006 (Ansi Institute of Management (Ansi Institute of Management Sciences) MardanSciences) Mardan Visiting Lecturer In Computer Science.Visiting Lecturer In Computer Science.
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DEFINITIONS
•one that computes: a programmable electronic device that can store, retrieve, and process data (Merriam-Webster’s Collegiate Dictionary)
•Planning or scheduling the performance of a task or an event.•The process of planning a sequence of steps for a computer to follow.•A logically arranged set of instructions to be performed by a computer.
com*put*er
Programming
Computer Programming
ComputerProgram
DEFINITIONS
• Algorithm :A step-by-step procedure for solving a problem in a finite amount of time.• Programming Language : A set of rules, symbols, and special words used to construct a computer program.
DEFINITIONS• Machine Language : The language, made up of binary-coded instructions, that is used directly by the computer.• Assembly Language : A low-level programming language in which a mnemonic is used to represent each of the machine language instructions for a particular computer.• Assembler :A program that translates an assembly language program into machine code.• Compiler : A program that translates a high-level language into machine code.•
DEFINITIONS
Source Program : A program written in a high-level programming language.
Object Program : The machine language version of a source program.
Syntax : The formal rules governing how valid instructions are written in a programming language.
Key Word : A word that has special meaning in C++; it cannot be used as a programmer-defined identifier.
http://sites.google.com/site/bcskardan/
WHAT WE WILL STUDY?
History of Computer Languages Variables & Constants Operators Conditional Statements Loops Arrays
One dimensional array Two Dimensional array
Functions Pointers
BOOKS
Object Oriented Programming in C++ (text Book) BY Robert Lafore 3rd Edition
C++ How to program (recommended Book) By Deitel and Deitel
HISTORY OF C++ C was developed in 1970 By Danis Ritche
C++ was developed in 1979 by bijarne Stroustroup
Super class of C Every Program written in C can be a legal program in
C++ but the reverse may not be true
Object Oriented Language
LETS START
C++ Program Structure
#include <iostream.h>#include<conio.h>Void main(){
cout<<“Welcome to the world of excitement”;getch();
}
FUNCTIONS
Functions are basic building block of C++ program
Function is a set related code that perform a specific task
Function name must be followed by parentheses
Each C++ program that you want to run must have ‘main()’ function
PROGRAM DESCRIPTION
There are two statement in the previous program
cout<<“Welcome to the world of Excitement”;
cout is a special word that is used as output statement
What ever you want to display on the screen can be done using cout.
This statement will display the phrase “Welcome to the world of excitement” on the screen
cout<<“Welcome to the world of Excitement”;
Notice the semicolon ‘;’ at the end of cout statement.
Semicolon inddicate the end of statement
In C++ each statement must be terminated with a semicolon.
getch();
Is it a function????
Whatever is followed by parentheses is a function
When the result is displayed on the screen, then this function will retain the result on the screen until you press a key from the keyboard
We will study its other usage in coming lectures
Lets start playing with computer
Run the first program of this semester
COMMENTS
Comments are used to describe the statements
They are ignored by compiler
They are only used for the programmer to understand the code
WHEN TO USE COMMENTS? Always good thing to use comments
Other programmer may not understand your code
They may need some short description about the code that you written
You may also need comments if revisit your own code after a long time
Do not put large details in comments Comments should be simple, clear and short
COMMENTS SYNTAX
Single Line Comments // this is single line comments
Multiple Line Comments
/* this is Multiline comments */
COMMENTS EXAMPLE
C++ Program Structure
#include <iostream.h>#include<conio.h>//main function start hereVoid main(){ /* this program display the text
phrase on the screen*/cout<<“Welcome to the world of excitement”;getch();//end of program
}
WHAT IF WE WANT TO STORE DATA IN A PROGRAM?
Write a program that add two numbers
How to put these two values in a program?
Variables are used for this purpose
VARIABLES
Variables are named memory locations that store data.
The value of variable may change during the execution of program
Each variable has …. Name Data Type
VARIABLE NAME
Variable name are called user defined Identifiers
Variable Name may have alphabets, Numbers and ‘_’ and nothing else.
Variable Name must start from Alphabet
C++ keywords cannot be used as variable name (we will discuss keywords in detail later)
C++ is case sensitive language so it distinguish between lower and upper case alphabets
DECLARING VARIABLES
When we need use a variable, we must declare it first.
Declaration introduce a variable’s name into a program and specify its type
Syntax Datatype variableName;
int var1; int var2; etc
DATA TYPES
In C++ each variable has their associated data type that tell the compiler that what type of value will be store in the variable
When the variable is declared, a space in computer is reserved.
That memory location then store the data
DATA TYPE IS C++
In C++ we have the following built in data type For integer
int reserve 2 bytesvalue range (-32768 to 32767)
long reserve 4 bytes value range (-2147483648 to 2147483647)
Real Numbersfloat reserve 4 bytesvalue range 3.4 x 10-38 to 3.4 x 1038
Double reserve 8 bytes value range 1.7 x 10-308 to 1.7 x 10308
DATA TYPES IN C++ (CONT’D)
Unsigned Data type
unsigned int (0 to 65,535)Same as ‘int’ but store only positive numbers
unsigned long (0 to 4,289,497,295)Same as ‘long’ but store only positive numbers
If we need to store only positive numbers then best option is to use unsigned data types
USING INTEGER DATA TYPE
Write a C++ program that add two numbers#include<iostream.h>
#include<conio.h>
void main()
{
int var1;
int var2;
var1 = 28;
var2 = 2;
int var3;
var3 = var1 + var2;
cout<<var3;
getch();
}
PROBLEM WITH “INT’ Write a program to divide 521/2
#include<iostream.h>
#include<conio.h>
void main()
{
int var1;
int var2;
var1 = 521;
var2 = 2;
int var3;
var3 = var1 / var2;
cout<<var3;
getch();
}
Integer when divide by integer always result in integer
At least one variable should be float when the result is expected in real number
i.e. int var1; float var2; float var3; var1= 521; var2 = 2; var3 = var1/var2 cout<<var3;
MULTIPLE DECLARATION ON SINGLE LINE
It is difficult to declare many variable of same type on separate lines
C++ allows us to declare same type of variable on single line i.e. int var1, var2, var3 ………..; float var1, var2, var3, ……….;
When declaring multiple variable on single line keep following points in mind Variable list should be separated by comma You can only declare same type of variable on single
line
#include<iostream.h>#include<conio.h>void main(){
int var1, var2, var3;var1 = 521;var2 = 2;var3 = var1 / var2;cout<<var3;getch();
}
VARIABLE INITIALIZATION
Initialization mean to put a value in a variable for the first time
Initialization can be done at any stage in a program
Normally we initialize variable immediately after declaration e.g. int var1; // declaration var1 = 25; //initialization
C++ allows us to declare and initialize a variable in a single line e.g. int var1 = 25;
DECLARATION AND INITIALIZATION ON SAME LINE
#include<iostream.h>#include<conio.h>void main(){
int var1 = 521, var2 = 2, var3;var3 = var1 / var2;cout<<var3;getch();
}
MEMORY CONCEPT OF VARIABLE
Now we now that when we declare a variable it reserve some memory that is used to hold user data
Lets explain this in detail
What is memory?? Hard Disk, Optical Disk, RAM, ROM
What is meant by memory when we talk in programming language?
RAM
RAM (RANDOM ACCESS MEMORY)
RAM is main memory that can be access directly by the processor
Every thing that we run on the computer must be in RAM
If it is not in RAM then we can not process it Then what about those program that are stored
on Hard Disk and we are still able to run it?????
When we click on the icon of a program, the program is first loaded into main memory and then its execution starts (It start working)
RAM (CONT’D)
So when we use a variable, the memory that it reserve must be in main memory(RAM).
Main Memory consist of large number of Cells called bytes
Each Cell has it own numerical value by which we identify each cell
These numeric value is called memory Address 1GB Ram has 1,073,741,824 cells (1 Billion)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
. .
. .
. .
. .
N-2
N-1
If we now the address of some empty cell then we can directly put our data in that specific cell i.e.
[13] = 24 It means that put value (24) at location number 13 What is problem with this method?
1) if we use this technique then the previous data written at that location will be overwritten and we will loss the previous data
2) We don’t know which memory location is in use and which one is free
3) after all this technique is difficult to memorize that which location store the specific data
So we need a human understandable name for these location
Variable are the human understandable name for these memory location
The compiler and operating System then keep track of the numeric values that are associated with these names
We only use variable to access and store values at that locations
VISUALIZE THE VARIABLE
int var1;
var1 = ;
cout<<var1;
25
0
1
2
3
4
5
6
7
8
.
.
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.N-1
var1
25
25